For moving a robot or for automatically operating a robot arm, it becomes necessary to plan a path thereof. “Randomized Kinodynamic Planning: S. M. LaValle and J. J. Kuffner, Jr.: Proc of IEEE Int. Conf. on Robotics and Automation, 1999” (“Non-patent Document 1” hereinafter) describes path planning using a stochastic mechanism. In the method described in Non-patent Document 1, one goal (final position: final configuration) is set for one start position (initial position: initial configuration), and a path is set via at least one midpoint (intermediate position: intermediate configuration) between them. At this time, a search space is, for example, a joint coordinate space in the planning of the path based on the midpoint, and the midpoint is set only one at a time.
The path setting using the search space such as the joint coordinate space is described in “Introduction to Robotics: Mechanics and Control (Chapter 7), authored by John J. Craig and translated by Hirofumi Miura and Isao Shimoyama, Kyoritsu Shuppan Co., Ltd., Gazette No. 109641” (Non-patent Document 2” hereinafter). Non-patent Document 2 describes a joint space method of describing a spatial-temporal path by a function of joint angle, as a method for determining a desired path of a robot in a space. In the joint space method, at least one midpoint is set between a start position (initial position) and a goal position (final position) of a path, and these are connected by a spline curve to generate a path.